Machine tool



Jan. 18, 1944. H, N, STEPHAN 2,339,435

I MACHINE TOOL 1 Filed April 18, 1940' t 1 l0 Shee INVENTOR. HALL/.5 hf .57r/a n/v ATTORNEYS Jan. 18, 1944. H. N. STEPHAN 2,339,435,

MACHINE 'I'OOL' Filed April 18, 1940 10 Sheets-Sheet 2 INVENTOR.

#444 /s N 512mm ATTORNEYS Jan. 18, 1944.

H. N. STEPHAN MACHINE TOOL Filed April 18, 1940 l0 Sheets-Sheet 3 v v INVENTOR. HALL/.5 A4 57'EP/ /fl/V BY- ATTORNEYS Jan. 18, 1944. s E 2,339,435

MACHINE TOOL Filed April 18, 1940 10 Sheets-Sheet 4 INVENTOR. H44 L /5 N .57'EPH/4/Y M WWX M ATTORNEYS Jan. 1 8, 1944. H. N. STEPHAN MACHINE TOOL Filed April 18, 1940' 10 Sheets-Sheet 5 v INVENT OR. HALL/5 N STEPHHN ATTORNEYS &

Jan. us, 1944. 3 v H. N. STEPHAN I 2,339,435

MACHINE -'I'OOL Filed April 18, 1940. 1o Sheets-Sheet 6 RHPID TEA VERSE HERD maL E v sum- 5w Mitt/011 I FED lNdAr ml 7 m m mrrw INVENTOR. HALL/5 N 57'E'PHHN 1km WaJM ATTORNEYS Jan. 18, 1944.

H. N. STEPHAN I MACHINE TOOL Ha W Filed April 18, 1940 l0 Sheets-Sheet 8 INVENTORQ ATTORNEYS Jan. 18,-1944. STEPHAN 2,339,435

MACHINE TOOL Filed April 18, 1940' 10 Sheets- -Sheet 9 a 1 c a A INVENTOR.

Hays N .57'EPHHH BY A 7 i2 flaw- 8 W ATTORNEYS Jan. 18, 1944. H. N. STEPHAN I I 2,339,435

MACHINE TOOL Filed April 18, 1940 10-Shmets-Sheet 10 FIG. 95

INVENTQR. M444 /5 N. STEP/VAN ATTORNEY.

Patented Jan. 18, 1944 MACHINE TOOL Hallis N. signor,

Machine Tool Com corporation of Ohio Stephan, Cleveland Heights, Ohio. asby mesne assignments, to The Lucas pany, Bratenahl, Ohio, a

Application April 18, 1940, Serial No. 330,413

Claims.

The present invention relates to machine tools.

An object of the invention is the provision of a novel indexing means for automatically stopping a power-driven member, such as the work table or spindle head of a boring machine, at a predetermined point and indicating the accuracy with which the member stops with reference to a predetermined desired place.

Another object of the present invention is the provision of a novel indexing mechanism including a precision dial indicator, end measuring rods, and/or inside micrometers, etc., for automatically stopping a power-driven member, such as the work table or spindle head, etc., of a. boring machine, at a predetermined pointor points and indicating on the precision dial indicator the accuracy with which the member stops at the desired place.

Another object of the present invention is the provision of a novel machine tool comprising a member movable relative to a support and power means for moving the same, and comprising means for automatically stopping the member at a predetermined point or points and indicating the accuracy with which the member stops at the desired place.

Another object of the present invention is the provision of a novel machine tool including a member movable relative to a support and power means for moving the same, and comprising means including end measuring rods and/or inside micrometers, etc., and a precision dial indicator for automatically stopping the member at a predetermined point or points and indicating the accuracy with which the member stops at the desired place on the dial indicator.

Another object of the present invention is the provision of a novel horizontal boring machine including a power-driven, vertically movable spindle head and a power-driven, horizontally movable table and comprising means for automatically stopping the head or table at a predetermined point or points and indicating the accuracy with which the head or table stops at the desired position.

Another object of the present invention is the provision of a novel horizontal boring machine including a power-driven, vertically movable spindle head and a power-driven, horizontally movable table, and comprising means including end measuring rods, and/or inside micrometers, etc., and a precision dial indicator or indicators for automatically stopping the spindle head or table at a predetermined point or points and indicating the accuracy with which the member or members stop at the desired place on the dial indicators.

Another object of the invention is the provision of a horizontal boring and milling machine comprising a motor for moving the spindle head, saddle, and table, adapted to be selectively connected to the various elements moved thereby by electrically-operated clutches, the control circuits for which motor and clutches comprise indicating lights indicating which element is connected to the motor and are so interlocked that under no circumstances can more than one of said elements be connected to the motor and only that element which is so indicated.

The present invention resides in certain details of construction and combinations and arrangements of parts and further objects and advantages thereof will be apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiment thereof described with reference to the accompanying drawings forming a part of this specification in which similar reference characters designate corresponding parts and in which Fig. 1 is a front elevational view of a horizontal boring machine embodying the present inventicn;

Fig. 2 is a diagrammatic view showing the power drive for reciprocating the saddle and table, and for raising and lowering the spindle head and the backrest block;

Fig. 3 is a sectional view approximately on the line 3-3 of Fig. 1;

Fig. 4 is an enlarged view of a portion of Fig. 3;

Fig. 5 is an enlarged view of a portion of Fig. 3;

Fig. 6 is a diagrammatic view of that portion of the drive for rotating and reciprocating the spindle which islocated in the base of the machine;

Fig. 7 is a diagrammatic view of the portion of the mechanism for rotating, feeding and traversing the spindle which is located in the spindle head;

Fig. 8 is a section through the backrest clamping mechanism approximately on the line 8-8 of Fi 1;

Fig. 9 is a view of the pendant control station; and

Figs. 10, 11, 12 and 13 are wiring diagrams of the electrical control.

Referring to the drawings, the machine shown therein comprises a base A, provided at one end with a spindle head column B formed with vertical ways Ill and II upon which a spindle head 0 is mounted for vertical movement. and at the other end with a backrest or outboard support column D slidably supported on horizontal ways l2 and I3, see Fig. 3, formed on the upper side of the bed. The ways l2 and II also support a saddle E having transverse horizontal ways l4 and I! on the upper side which in turn support a work table-F. The backrest column D is provided with vertical ways I3 and I1, see Fig. 8, upon which a. backrest block G is mounted for vertical movement.

The spindle head which is counterbalanced by a weight (not shown) is adapted to be moved vertically along the ways It andv II by a lead screw l3 rotatably supported in the machine in a suitable manner and having threaded engagement with a nut fixed in the. spindle head. In addition to being rotatable in opposite directions, the tool spindle I9 is movable in opposite directions longitudinally of its axis of rotation at different speeds to effect both feeding and traversing movements. The backrest block'or outboard support G is movable simultaneously withthe movement of the spindle head C by a vertical lead screw 20 located within the backrest column D and connected to the drive or mechanism for rotating the screw IS. The saddle E is movable longitudinally of the tool spindle along the ways I2 is movable transversely of the tool spindle along the ways I 4 and I at different speeds by mechanism herein-after specifically referred to.

The speed and direction of rotation of the spindle, etc., and the aforesaid movements of the various elements, such as the feed and rapid traverse of the spindle, head, saddle, table, etc., are performed by power and their operation may be controlled from any convenient place about the machine. In the embodiment of the invention shown, five electric motors are employed; a reversible motor 2| hereinafter referred to as the feed and rapid traverse motor, suitably supported onthe bed within a guard 22 adjacent to the left-hand end of the machine; a' reversible main driving motor 23 arranged. for ceilin mounting, also enclosed within the-guard22; a spindle rapid traverse, reversible motor 24 mounted on the head 0; a reversible motor 25 for clamping and releasing the backrest block; and a reversible motor 26 (not shown on the machine) for moving the backrest column D.

The feed and rapid traverse motor 2| is connected to the saddle and table feeding and rapid traversing mechanism and to the spindle head and backrest raising and lowering mechanism, the

and I3 and the table F 1 reference character K, or at arelatively high or traversing rate through a normally disengaged disk clutch L, a shaft 34, and the over-running clutch mechanism K. The feed change gears. etc.. are housed within a suitable gear box in the base A. Through the medium of the transmistiveiy, rotated at a high rate of speed. The gear main driving motor 23 is connected to the spindle rotating and feeding mechanism, and the small reversible motor 24 on the. head actuates the rapid traverse for the tool spindle through an overrunning clutch. The feed and main driving motors are adapted to be selectively connected to the various operating elements through the medium of suitable speed change transmissions, shafts, gears, clutches, etc., the controls for which are located on or adjacent to the base A, spindle head C, and/or pendant control station H fixed to the lower end of a tubular rod connected to a universally movable arm 21 by a flexible cable 28.

The reversible motor 2| is operatively con-- nected to a horizontally extending shaft 30 rotatably'supported in the base A, through the medium of a V-belt drive 3| and spur gears 32 and 33. From the gear 33 the drive is either at a relatively slow or feeding rate through a variable feed change transmission, designated generally by the reference character J, and an overrunning clutch device, designated generally by the '33 is keyed to the driven shaft of the feed change transmission .1 and the gear 35 is journaled on the shaft 34. The driving element of the friction clutch L is splined to a shaft 34, which shaft is in axial alignment with the shaft 3|! and is adapted to be actuated to engage the clutch L upon energization of an electrically-operated solenoid 36 connected to one lever of a bell crank lever 31 pivoted on the frame, the other lever of which is connected to a member which in turn actuates the clutch elements.

The last or driving gear 33 of the transmission J is continuously in meshwith a gear 44 which forms the low speed element of the overrunning clutch mechanism K. The gear 40 is rotatably supported on the shaft 34 and has formed integral therewith the driving element 4| of a normally engaged toothed clutch, the driven element 42 of which is splined on the shaft 30. The left-hand end of the driven element 42, as viewed in Fig. 2,

has a plurality of sloping teeth or cam surfaces 43 which cooperate with similar teeth 44 on a high speed driving member 45 fixed to the right-hand end of the high speed shaft 34. The member 42 is continuously urged towards the left, as viewed in Fig. 2, by a compression spring 43 interposed therebetween and the gear 40. The construction is such that the shaft 3|! is normally connected to the transmission J through the normally engaged clutch elements 4| and 42 and the gears 39 and 40, with the shaft 34 rotating at the same speed as the shaft 30 due to the engagemerit of the teeth 43-and 44.

Upon engagement of the friction clutch L, the shaft 34 is rotated at a higher rate of speed than the shaft 30. This diiference in speed causes the teeth 43 of the slidable clutch element 42 to climb the teeth 44 of the element 45 carried by the shaft 34, with the result that the slidable clutch element 42 is moved towards the right, disengaging the teeth thereof from the teeth of the clutch element 4|, which in turn disengages the low speed drive. Thereafter, the shaft 3|! rotates at the same high speed as the shaft 34. Movement of the member 42 towards the right is limited by the compression spring 46, and the construction is such that the cooperating teeth 43 and 44 are never permitted to clear each other. Both sides of the teeth 43 and 44 are inclined which makes the device operable for either direction of rotation of the motor 2|. When the clutch L is released, the spring 43 reengages the cooperating clutch teeth of the clutch elements 4| and 42, and reconnects the feed to the shaft 30 in place of the rapid traverse.

The shaft 30 is also in axial alignment with a third shaft 41 to which it is connected by a normally engaged overload release clutch 4|, operable in either direction. The right-hand end of the shaft 41, as viewed in Fig. 2, is provided with a gear continuously in mesh with the gear 5| rotatably supported on a shaft 52 to which it is adapted to be selectively connected by a norassacsa.

mally disengaged positive'drive' clutch M, the. driven element 58 of which is splin'ed on the left-hand. end of the shaft 52 and provided with clutch teeth adapted to engage clutch teeth formed on the hub of the gear II. The shaft 52 is operatively connected in a suitable manner to a lead screw 58 extending longitudinally of the machine and rotatably supported in the. base A, which lead screw moves the saddle E along the ways I: and I8.

The movable element 58 of the normally disengaged clutch M is adapted to be moved toward the right, as viewed in Fig. 2, to engage the clutch and thereby connect the lead screw 58 to the shaft 81 and in turn the feed and rapid traverse motor 2| by an electric solenoid 55 suitably supported in the base A of the machine, the armature of which solenoid is connected to the slidable clutch element 58 by a slidable rod 58 and a.

pivoted yoke member 51. The clutch is normally held in disengaged position by a compression spring 58 surrounding the rod 58 and interposed between the frame of the machine and a shoulder on the rod 58. A hand feed is provided for the saddle E in the form of a rotatable shaft 88, the front end of'which projects to the front of the machine where it is arranged for the reception of a hand crank.

The table F is adapted to be moved along the ways I and I of the saddle Eby a lead screw 88 rotatably supported in the saddleand operatively connected to a suitable nut fixed to the underside first of which is keyed to the forward end of the of the table. The lead screw 88 is adapted to be selectively connected to the shaft 41 in a manner similar to that in which the lead screw 54 is selectively connected to said shaft 41, which manner of connection has just been described. The gear 5| journaled on the shaft 52 is continuously in mesh with a gear 8| which in turn is continuously in mesh with a gear 82 Joumaled on a shaft 83 rotatably supported in the base A I and extending substantially the length thereof.

The gear 82 is adapted to be selectively connected to the shaft 88 by a normally disengaged, positive drive tooth clutch N similar to the clutch M. The slidable element 88 of the clutch N is splined to the left-hand end of the shaft 83 and is moved towards the right to engage the teeth thereof with teeth formed on the hub of gear 82 by an electric solenoid 85, the armature of which is adapted to be connected to the movable clutch element 84 through the medium ofa slidable rod 88 connected to the armature and to one end of a pivoted lever 81, the opposite end of which lever is connected to a slidable rod 88 which in turn is connected to a pivoted lever 88 carried by a short shaft joumaled in the frame, to the lower end of which shaft is secured a clutch operating yoke 18 that engages in a groove formed in the movable clutch member 88. The pivoted lever 88 is continuously urged in a clockwise direction, as viewed in Fig. 2, by a compression spring ll interposed between the frame of the machine and a shoulder on the lever 88. The construction is such that upon energization of the solenoid 85, the armature is moved towards the left, rotating the member 88 in a counterclockwise direction and engaging the clutch N. I

The shaft 83 is operatively connected to the lead screw 80 in the following manner: A gear 12 carried by the saddle E and splined to the shaft 83 is continuously in mesh with a gear 18 journaled on a shaft 14 and formed integral with a bevel gear l5. The bevel gear 15 meshes with a bevel gear IS-fixed to the rear end of the transshaft 11 and is continuously in mesh with the idler gear 18, which in turn meshes with the gear keyed to the lead screw 88. The forward end of. the lead screw is provided with a worm wheel 8| continuously'in mesh with the worm 82 fixed to a shaft 88 journaled in the saddle and extending longitudinally of the machine. The

ends .of the shaft 88 project from opposite sides of thesaddle and are arranged for the reception of a hand crank.

The lead screw l8 which raises and lowers the spindle head and the lead screw 28 which raises and lowers the backrest block are adapted to be selectively connected to the shaft 81 in a manner similar to that in which the lead screws 58 and 88 are connected to the shaft 81. For this purpose, the gear 82 is continuously in mesh with a gear 88 Journaled on a longitudinally extending shaft 85 to which it is adapted to be operatively connected by a normally disengaged tooth clutch 0, similar in construction to the clutches M and N previously referred to, the movable element 88 of which is splined to the shaft 85. The shaft 85 carries two bevel gears 81 and 88 continuously in mesh with bevel gears 88 and 88 fixed to the lower end of the lead screws l8 and 28, respectively. The gear 88 is splined to the shaft 85 and moves therealong with movement of the outboard column D.

The movable element 88 of the clutch O is adapted to be shifted longitudinally of the shaft 88 to engage and disengage the clutch by a clutch yoke member 8l formed integral with the clutch yoke member 18. The clutch yoke 8| is adapted to be rotated in a clockwise direction to engage the clutch O by an electric solenoid 82, the armature of which is connected to the lower end of the pivoted lever 81 by a slidable rod 88.

A compression spring 88 surrounding the rod 88 and interposed between the frame of the maintains the clutch O disengaged. The gear 88 fixed to the lower end of the lead screw I8 is also engaged by a bevel gear 85 fixed to the rear end of a shaft 88 projecting to the front of the machine where it is arranged for the reception of the hand crank. This construction provides means for manually raising or lowering the spindle head and the backrest block. The slidable members 58 and 88 are mechanically interlocked by a Y-shaped member 81 plvotally supported intermediate its ends by the frame of the machine in such a manner that by moving one the other can be pulled into its neutral position. The lower end of the member 81 is pivotally connected to the member 58 and a pin 88 carried by the member 88prolects between the upper ends thereof.

The transmission J shown comprises four shiftable elements for obtaining different feeds.

These elements may be moved in any convenient .described in detail. The preferred form of mechanism is shown in a copending appl cation of Henry M. Lucas et al., Serial No. 243,616, filed December 2, 1938.

From the foregoing, it will be apparent that the saddle, table, spindle head, and backrest block may be. operated selectively either manually or by the reversible feed and rapid traverse motor II. If operated by the motor M, the

movements may be in either direction and at either a'feed-rate or a rapid traverse rate. The arrangement of the clutches for moving the saddle, table, and spindle head and backrest block is such that it is impossible to simultaneously engage two clutches. The manner in which the solenoids 00, BI, and 92 are energized will be hereinafter more specifically referred to. The construction also includes three 7 double throw electric switches I00, vI0I, and

switch I00 is connected to the rod 56, and one of the three circuits through the switch IN is closed when the clutch O is engaged and when discharged the other two circuits are closed, and

vice versa. The switch I02 is operatively connected to the rod 00 in such a manner that a normally open circuit therethrough is closed and two normally closed circuits therethrough are opened when the clutch N is engaged, and vice versa. The function of these switches will be hereinafter referred to. The machine also includes a number of normally closed limit switches which stop the feed and rapid traverse motor 2| when the particular element, that is, head, saddle, or table, being moved thereby, reaches the end of its travel. These limit switches are interlocked in a manner hereinafter'described so that the limit switches of the elements not being moved will not interfere with the actuaassasse shown in Fig. 3. The lever is adapted to be shifted from the full line position shown in Fig. 4 tothe dotted line position shown therein to open the normally open contacts of switch Ill and discontinue the rapid traverse movement by inciined'cam surfaces II! on the stops I 00, III, III,= and H2 previously mentioned, and an adjustable stop H0. The lever H4 is adapted to be rotated from the full line position shown in Fig. 4 to the dotted line positionshown therein by the cam surfaces II! as they pass over the upper end of the lever irrespective of the direction in which the table is moved. An inclined x cam surface I" on an adjustable stop Ill moves the lever I I4 in the opposite direction; The conand H0. When the lever H4 is rotated to the tion of the element which it is desired to feed or rapid traverse.

Reciprocation of the table F is adapted to be automatically controlled by five limit switches I08, I04, I05, I00 and I01. The limit switches I03, I04, and I05 are normally closed switches and control the feed movement, and the limit switches I00 and I01 control the rapid traverse movement. The table back and forward limit switches I03 and I04, respectively, are adapted to be opened by downwardly extending projections I00 on a plurality of stops I09, IIO, III and H2, respectively, the first two of which stops are fixed to amember carried by the table proper whilethe second two are adjustable therealong. The downwardly extending projections on the stops are adapted to engage the upper end of a lever II3 pivotally supported in the saddle E, the lower end of which lever is adapted to engage the operating arms of the limit switches I03 or I04, depending upon the direction in which the lever is rotated. The adjustable stops III and H2 provide means for automatically stopping the table at any place intermediate its extreme limits and the fixed stops I09 and H0 limit the extreme movement of the table.

The double throw table jump feed rapid traverseswitch I06 is so located in the control circuit that the solenoid 30 is energized and the rapid traverse drive made operative upon the closing of normally open contacts thereof. The switch is operated so as to close the normally open contacts and open the normally closed contacts thereof by the lower end of a lever II4 pivoted in the saddle E, which lever has three positions; the full line and the dotted line positions shown in Fig. 4 and the full line position the table.

positionshown in Fig. 3, it is entirely clear of all of the stops and the tablecan be moved without danger of the rapid traverse being automatically thrown in. The same result .could be accomplished, less conveniently, however, by removing the stop or stops 8.

Manual means is provided for rotating the lever II4 from one position to another in the form of a lever I I0 operatively connected thereto through mechanism (not shown) which lever has three positions corresponding with the three positions of the lever H4. The saddle E has a groove formed on the upper side ofv an extension thereon adapted to receive end measuring rods I20, the left-hand end of which. as viewed in Figs. 3 and 4. cooperate with an anvil on an adjustable block I2I carried by the table F. The construction is such that the adjustable block I2I does not interfere. with the stops previously referred to.

The right-hand end of the measuring rods cooperate with a table dial indicator I22 and the limit switch& I05 and I0'I, all of which are enclosed within a housing I23 bolted or otherwise suitably secured to the front end of the saddle.

the speed ofmovement of the table from rapid traverse to feed. Further movement of the member I24 actuates the dial indicator I22. The plunger I28 of the dial indicator I22 projects through the gauge housing and the right-hand end thereof, as viewed in Fig. 5, is adapted to engage the operating arm of automatic index forward limit switch I05 and open the circuit therethrough stopping the forward movement of The automatic index switches I05 and I01 are of such construction that the opening of the contacts can be accurately controlled. The particular switches shown are known as "micro" switches. The accuracy with which the table stops, at any predetermined place is indicated on'the dial indicator I22. The housing I23 ,is ordinarily closed by a removable cover I36 provided with a window through which the dial indicator I22 can be reached and observed. The indexing mechanism just described operates in the following manner:

Assuming that the table has been previously stopped by the automatic index forward feed limit switch I" and it is desired to move the table forward a predetermined amount, for example, six inches, with the present construction it is only necessary to remove a suitable length -of rod gauge, in the present instance a six inch stops and the accuracy with which the table has moved the desired distance can be read or checked on the dial indicator I22 which has previously been set at zero. With the construction shown the table can be repeatedly stopped within a fraction of a thousandth of an inch of the desired position.

The upper and lower limits of movement of the spindle head C are controlled by two normally closed limit switches I35 and I36 fixed to ,the spindle head C and adapted to cooperate with upper and lower adjustable stops carried on the thra rear splines of a vertical six-spline shaft I31. The stops have projections thereon which make it impossible to move the spindle head C past the same. The limit switches I35 and I36 are not shown on the machine but their location in the electrical circuit will be hereinafter referred to. A plurality of members I36 adapted to be clipped on the front splines of the shaft I31 and adjustable therealong provide means for supporting end measuring rod I39, the lower end of which is supported on an anvil carried by a projection I40 on the spindle head 0. The upper end of the end measuring rod or rods I39 is adapted to cooperate with a spindle head dial indicator gaug I22 and two switches I05 and I01 enclosed within a housing I23.

suitably secured to the upper end of the shaft or rod I31. The construction and the operation of the spindle head dial indicator I22, the limit switches I05 and I01, and the housing I23, etc., are the same as the dial indicator I22, the switches I05 and I01, the housing I23, etc., and will not be described in detail again. Sufiice it to say that as the spindle head is moved in an upward direction the upper end-of the top measuring rod engages a member similar to the member I24 slidably supported in an aperture in the housing I23. As this member is forced inwardly by the measuring rods the upper end thereof first opens the spindle head automatic index rapid traverse up switch I01 changing the speed of movement of the head from rapid traverse to feed. Further movement of the member actuates the dial indicator I22. The plunger of the dial indicator gauge I22 projects through the housing of the dial indicator and the upper end thereof is adapted to engage and open the spindle head automatic index feed limit switch I05 stopping the spindle head. The accuracy with which the spindle head stops is indicated on the dial indicator I22.

The saddle right and backrest column left limit switch m and the saddle left limit switch I46 (not shown on the machine) are located underneath the rear of the saddle on the left and right-hand sides, respectively, are adapted to be opened upon engagement with stops located on the backrest column and on the'bed of themachine, and limit the travel of the saddle towards the right and left, respectively, and the,

backrest column towards the left. The spindle I6 is adapted to be rotated at var ious rates of speed by the main driving reversible motor 23 through the medium of speed change gearing, designated generally by the reference character P, see Fig. 6, housed in'a suitable gear box supported in the bed of the-machine; a vertical shaft I50, the lower end of which is rotatably supported in the gear box while the upper end is supported in the head column B; and back gears, designated generally by thereference character R, located in the spindle head C. The motor 23 is connected to the drive: shaft I5I of the speed change transmission P by a-V-belt driveand spur gears I52 and I53, the former of which is fixed to a shaft carrying the driven pulley of the V-belt drive while the latter is fixed to the shaft I5I. The driving shaft I54 of the transmission P is connected to the lower end of the vertical shaft I53 by miter gears. The speed change transmission P provides nine different speeds and comprises gear clusters I55 and I56 slidably supported on the shafts I5I and I54, respectively, and adapted to cooperate with gear clusters I51 and I53 fixed to an intermediate shaft I59.

The gear clusters I55 and I56 are adapted to I be shifted lengthwise of the shafts I5I and I54 upon which they are slidably splined to obtain the various speeds by any suitable mechanism. The particular mechanism illustrated forms no part of the present invention per se and will not be illustrated and described herein in detail. Suflice it to say that the mechanism shown, which is the preferred mechanism, is similar to that.

disclosed in the aforesaid copenrling application of H. M. Lucas at al., Serial No. 243,616, to which reference is made for a detailed description thereof. v

The driven shaft of the back gears R is rotatably supported in the spindle head and is connected to the upper end of the vertical shaft I50 by a bevel gear I6I carried by the spindle head and splined to the shaft I50. The bevel gear I6I meshes with a bevel gear I62 fixed to the .left-hand end of the shaft I60. The spindle I9 is slidably keyed within a spindle quill I63rotatably supported by suitable hearings in the spindle head C, which spindle quill has a gear cluster comprising the gears I64 and I55 fixed thereto.

*The gears I64 and I65 are adapted to be selecing the gears I66 and I63 is adapted to be shifted along the shaft I60 by a hand lever I1I fixed to the front end of a horizontal shaft journaled in the spindle head, the rear end of which shaft carries a yoke member engageable with the gear cluster.

The spindle I3 is adapt d to be fed or rapid traversed in either direction by a lead screw I12 rotatably supported in the spindle headextension and having threaded ensasementwith a twopiece nut I15 located within the feed slide I15 adjacent to the left-hand endof the spindle I and connected thereto in a suitable manner. The leadscrew Il2isadaptedtoberotatedineither direction and at different speeds from the spindle quill I55 through the medium of spur gears I15 and I15, the former of which is fixed to the lefthand end of the spindle quill while the latter is fixed to the right-hand end of a shaft I'I'| jourmind in the spindle head and which forms the driving shaft of a feed speed change transmission, designated generally by the reference character S, housed within a suitable gear box in the spindle head. The gear I18 which forms the driving element of the feed change transmission s is operatively connected to a horizontal shaft "5 journaled in the spindle head through the medium of a gear I55 which forms the low speed element of an overrunning clutch transmission T similar to the transmission K previously described. The shaft I15 is adapted to be selectively rotated at a high rate of speed in either direction by the reversible rapid traverse motor 25, which motor,

is operatively connected to the high speed element III of the overrunning clutch transmission T.

The shaft 115 is adapted to be operatively connected to a horizontal shaft I 52 journaled in the I55 and I8! are adapted to be selectively connected to the shaft I52 by a shiftable clutch element I55 splined on the shaft I52 between the gears I55 and I51, opposite ends of which clutch element are provided with clutch teeth adapted to cooperate with similar clutch teeth formed on the adjacent sides of the hub of the gears. The clutch element I85 is normally maintained in an intermediate or neutral position by a pair of springs I55 and Ill but is adapted to be shiftedtowards the left to drive the shaft I52 from the gear I85 or towards the right to connect the gear I51 with the shaft I52 by electric solenoids I52 and I55, respectively.

The armature of the solenoid I52 is connected to a slidable member I55 provided with an inclined cam slot I55 within which a roller carried by a longitudinally slidable rod I55 engages The armature of the solenoid I55 is connected to the bar I55 in a manner similar to that in which the armature of the solenoid I52 is connected thereto, except for the fact that the cam slot I5I in the member I55 corresponding tothe member I55 is inclined in the opposite direction to the slot I55. The lower ends of the cam slots are widened so that the operation of one of the members I55 and I55 will not be interfered with by the other. The slidable member I55 has a clutch yoke fixed to the right-hand end thereof which enga es in a a groove formed in the shiftable clutch member I55, The bar I55 is normally held in such a position that the clutch element I55 is in neutral station H previously referred to.

reference character U, the driven gear 2" of,

whichis fixed to the end of the lead screw I12.

Adjacent to its right-hand end. th shaft I52 is operatively connected to a spindle feed hand 'wheel 252, a crank 255 and fixed and adjustable dials, etc.,v as is known in the art. The mechanism shown per se forms no part of the present invention, is similar to that described in the aforesaid copending application of H. M. Lucas et aL, Serial No. 243,616 and will not be described in detail. Like the machine shown in said application the present machine includes two spindle limit switches 255 and 255 adapted to be opened by an odjustable trip 255. The switches 255 and 255 are secured to the rear side of the front of the spindle head and the construction is such that the spindle feed can be automatically stopped at any desired point by setting an adjustable dial which carries the trip 255.

The backrest block G is adapted to be clamped to and unclamped from the ways I5 of the column D by the electric motor 25 carried thereby. The circuit to the motor 25 i controlled by a double throw clamp switch 255, not shown on the machine, operatively connected to a lever 25I which operates the spindle head clamp in such a manner that when the lever 25I is in a position to clamp the spindle head C to the column B the normally open circuit therethrough is closed, and vice versa. The construction is such that the 1 motor 25 is operated to clamp and unclamp the backrest block simultaneously with the clamping and unclamping of the spindle head C. The circult to the motor 25 includes a normally open backrest block clamp motor limit switch 252 fixed to a clamp plat 255 and operated by a pivoted lever 255, one end of which engages a threaded sear member 255. The circuit through the switch 252 is maintained closed by the lever 255 while the backrest block is clamped to the column D. The control for th motor 25 is also interlocked with the main control in such a manner that the solenoid 52 cannot be actuated to connect the lead screws I5 and 25 which raise and lower the spindle head and backrest block, respectively, with the feed rapid traverse motor 2| while the spindle head and backrest block are clamped to the columns B and D, respectively.

The backrest column D may be moved along the horizontal ways I2 and I5 of the bed A either manually or by a motor 25, not shown on the machine, the operation of which motor is adapted to be controlled by two normally open push button switche 25! and 255 located on the front side of the backrest column D underneath a manual lever 255, adapted to clamp the backrest column to the ways I2 and I5 in any adjustedposition. The construction is such that. the push button switches 251 and 255 cannot be operated unless the lever 255 is in a position to unclamp the backrest column from the ways.

In operation, after the desired feeds have been selected, the remaining operations of the machine are controlled from the electrical control The various selecting switches, push button switches, etc., of the control station H are so arranged .that their position corresponds to the direction of movement initiated or controlled thereby.

The electrical control station E has twenty-one push buttons and four selecting switches. The

feed push buttons for the head, saddle, and table are arranged in groups and are located to give directional control. In othcrwords, the button of each feed is on theside in a direction in which the feed will take place when the button is pressed. Each group has two continuous feed push buttons and two inch push buttons. In

the center of each group is .a selecting switch which, when turned on, makes the push buttons in that particular group operative and cuts out through relays all other groups of feed buttons and selecting switches. The selecting switches also make operative only the limit switches for the particular unit or element selected and cut out the limit switches for the other units or elements. This arrangement makes it possible to leave one or more of the units on a limit switch and move another unit as desired. When any one of the above-mentioned selecting switches is turned on and the circuit therethrough established, a white pilot light, located adjacent to that particular switch, lights. This tell at a glance which group of push buttons is operative. The two continuous feed buttons in each group also have light bulbs therein which light when the push button is pressed momentarily and remain lighted so long as the feed is operating. This indicates which unit is being fed and in what direction. One of.

the principal features of the present control resides in the fact that under no circumstances can either the head, saddle or table be connected to the feed and rapid traverse motor 2| other than the one indicated by the indicating lights, so that the operator always knows which, if any, of the units is operative.

In the embodiment of the invention shown, the spindle head continuous feed and inch feed push buttons are designated by the reference characters 240 and 2H, and 242 and 243, respec-. tively. These buttons, together with the selecting.

switch 244 and the indicating light 245 associated therewith, are grouped together and the continuous feed button 245 which causes the spindle head C to move in an upward direction is located above the continuous feed button 24lwhich initiates a continuous feed in a downward direction. The same is true of the "inch push buttons 242 and 243. In a similar manner the saddle continuous feed and "inch" feed buttons 245 and 241, and 243 and 249, and the selecting switch 250 and indicating light 25! associated therewith are grouped together adjacent to the lower end of the front panel of the control station H. Since the saddle E moves longitudinally of the machine, the push button 245 which initiates a movement of the saddle towards the right is located at the right-hand side of thepanel, while the push button 241 which initiates a movement in the opposite direction is located adjacent to the left-hand side thereof. The same is true of the inch" feed buttons 245 and 243.

The table continuous feed and inch feed buttons 252 and 253, and 254 and 255, respectively, and the selecting switch 255 and the indicating light 251 associated therewith are located adjacent to the lower end of the right-hand side panel of the electrical control station. Since the table F moves transversely of the machine, these buttons are grouped on the right-hand side panel of the control station, and the continuous feed button 253 which initiates a movement towards the rear is located to the rear side of the panel, while the continuous feed button 252 which initiates a movement of the table towards the front is located adjacent; the front side of the panel. The same is true of the inch iced buttons 254 and 255. None of the continuous feed push button switches are operative unless the spindle is rotating.

The selecting switches 244, 255 and 255, besides separating electrically the particular unit selected from the other units, energize the solenoids 92, 55 and 55, respectively, connecting the particular unit selected .to the feed and rapid traverse motor 2|, thus selecting the unit to be moved by power. The respective solenoid will remain encrgized so long as the selecting switch associatedtherewith is turned on except during the time that an inch" or, "jog feed push button switch 255, hereinafter referred to, located on the bed A is depressed. All the controls located on the pendant control station H are, rendered inoperativeduring the time Jog push button switch 255 is depressed. After the push button switch 258 has been released, the selection remains as it was prior to pushing the switch, but spindle rotation and any continuous feed which may have been operating is no longer in operation, and if it is desired to continue the previous feed, it must again be started by depressing the particular feed push button in question. To aid the springs 55,

II and 94 in disengaging the respective clutches, one of the idle solenoids is momentarily energized, in a manner hereinafter described, when the selecting switch associated therewith is turned ofl" or jog push button switch 259 depressed,

thus pulling the clutch into a neutral position.

A single push button switch 253 is employed for controlling the rapid traverse movements of the head, saddle, and table. This push button switch is located on the front panel of the pendant control station and, upon being de- .pressed, closes the circuit to the solenoid 35 through relays in a manner hereinafter referred to, connecting the shaft 41 to the motor 2| through the friction clutch L, etc. The rapid traverse is not effected unless thefeed for the particular element or unit that it is desired to rapid traverse is in operation, and, when ini tiated the rapid traverse will be in the direction of the feed movement. .When desired'all feeds including the spindle feed can be stopped by depressing a stop all feeds push button switch. All feeds and the spindle rotation can be stopped by depressing the stop all feeds and spindle rotation push button switch 25| projecting from the bottom of the pendant control. 1

The fourth selecting switch 252 of the pendant control station H is the spindle feed directional switch. When this switch is turned to the right, the spindle feed, when operated, will be to the right, and when turned to the left, the direction of feed will be to the left. The spindle feed is.

upper end of the front panel of the pendant control station H. Depressing the spindle feed.

'. push button 253 energizes one or the other of the solenoids I82 and I93. depending upon which direction of feed has been selected by the spindle feed direction selecting switch 252. Once the push button 253 has been depressed after the spindle feed directional I switch 252 has been turned on, the circuit to the particular solenoid energized remains closeduntil the feed stop all feeds push button switch 25l is depressed or until the selecting switch 252 is turned ofi. The spindle start push button switch 263 has a light therein which is energized whilcthc-feed is opselecting switch 262 wouldythen no longer indicate thefeed direction, but thisis prevented byso wiring the machine" that reversing of the direction of the spindle also transposesthe spindle feed solenoids I62 and I 63 so that when the spindle feed switch 263 is again depressed, the opposite solenoid will be energized'and the feed will be in the same direction as previously selected. Thetwo push buttons 264 and 265 for controlling the rapid traverse motor 24 are so mounted in the front panel of the pendant control station H that when the right-hand button 264 is depressed, the spindlewill be rapid-traversed to the right, and when the left-hand button 265 is depressed, the spindle will be rapid-traversed to the left. To make the spindle rapid traverse push buttons operative, however, the spindle feed selecting switch 242 must be in one of its on positions. The rapid traverse push buttons 264 and 265 always move the spindle in the aforesaid directions, that is, the button on the right always moves the spindle to the right and the button on the left always moves the spindle to the left irrespective .of-the direction of spindle feed se-- lected by the spindle feed direction selecting switch 262. This is accomplished by having the spindle feed solenoid relays control the direction of rotation of the spindle rapid traverse motor 24.

Continuous rotation of the spindle is is con trolled by three push button switches 266, 261 and 266. The'flrst two button switches 266 and 261 cause the spindle to rotate in opposite directions, down in front and up in front, respectively. The third push button switch 266 logs the spindle down in front. Depressing the push button switch 266 stops both motors 2| and 23. The jog push button 256 previously referred to jogs both the feed and rapid traverse motor 2I and the main motor 23. When the push button switch 256 is depressed slightly, all feeds are thrown out and the rotation of all motors is stopped. When depressed further, both motors 2| and 23'start and continue to run as long as the button is held in its extreme depressed position.

Figs. 12, 13, 14 and 15 are wiring diagrams of the electrical hook-up of the machine. Referrin to these figures, it will be seen that all the push button switches employed, with the exception of the push button switches 231, 238, 266, 26I, 264, 265 and 266 are double-throw switches having two or more sets of contacts, oneor more sets normally closed and the other set or sets normally open. When the spindle forward push button switch 266- is depressed, a circuit is completed from the line*L-I through normally closed upper contacts of the jog push button switch256, wire 21I, normally closed'c'ontacts of the spindle stop push button switch'266, wire 212, normally closed contacts of the spindle jog push button switch 266, wire 213, normallyficlosed contactsof the spindle forward push button switch '261','wire 214, normally open contactsof the push button switch 266, wire 215, operating solenoid 216 of relay 211,

wire 216, and overload contacts 21.6 on motor control panel 266 which controls the motor 23,

to line L-2.

Energization of the solenoid 216 closes the normally open contacts 262 and 263 of relay 211, the

- former of which completes a circuit from the line L-I through log push button switch 256, wire 2'", spindle stop push button switch 266, wire 212, jog push button switch266, wire 213, spindle forward push button switch 261, wire 214, contacts 262 of relay 211, wire 264, operating solenoid 265 of motor control panel 266, wire 216, and

overload contacts 216 to L-2, thus energizing the operating solenoid 265 of motor control panel 286, closing the main contacts 266, 261, and 266 connecting the motor a to the main line L--I, L-2, and L-3, causing the motor to rotate in a direction to rotate the spindle I6 down in front,

commonly referred to asv forward. "The second set of contacts 263 of relay 211 complete a holding-in circuit for the solenoid 216 of the relay 211 through the normally closed contacts of the spindle reverse push button 261, wire 214, contacts 263, wire 215, etc., which maintains the relay closed after the push button switch 266 has been released. The motor 23 continues to rotate until the solenoid 265 of the motor control panel 266 is deenergized, which may be accomplished by slightly depressing either of the jog push button switches 256 or 266, or the spindle stoppush button switch 268 on the pendant control.

#TO rotate the main motor 23 and in turn the spindle I6 in the reverse direction, the spindle reverse push button switch 261 is depressed, closing the normally open contacts thereof and completing a circuit from the line L-I through the normally closed contacts of the jog push button switch 258, wire 21 I, stop push button switch 266, wire 212, jog push button switch 266, wire 213,

spindle forward push button switch 266, wire 266,

normally open contacts of spindle reverse push button switch 261, wire 266, operating solenoid 26I ofrelay 262, wire 216, and overload contacts 216 to L-2. Energization of the operating solenoid 26I of relay 262 closes the normally open contacts 263, 264, 265, and 266, and opens the normally closed, contacts 261 and 266. The closing of the normally open contacts 263 of relay 262 completes a circuit from the line L-I through jog push button switch 256, wire 2", stop push button switch 268, wire 212, jog push button switch 266, wire 213, spindle forward push button switch 266, wire 266, contacts 263, wire 266, operating solenoid 366 of motor control panel 266, wire 216, and overload contacts 216 to L2. l iergization of the operating solenoid 366 of l Lotor control panel 266 closes the main contacts 36I, 362, and 363 thereof, connecting the motor 23 to the line, causing it to rotate in a direction to rotate the spindle up in front, commonly referred to as reverse. The motor 23 continues to panel 266 is deenergized in a manner previously referred to.

The spindle may be jogged in a forward direction by depressing the spindle jog push button switch 266 to close the normally open contacts thereof and complete a circuit from the line L-I through jog push button switch 256, wire 21I, spindle stop Dushbutton switch 266, wire 212, jog push button switch 269, wire 264, operating solenoid 265 of motor control panel 266, wire 216, and overload contacts 216to line L-2. Energization of the operating solenoid 265 of motor control panel 266 closes the main contacts 266, 261, and 266 connectingthe motor 23 to the line in such a manner that the motor rotates the spindle in a forward direction. The motor continues to operate as long as the log push-button 218, and overload contacts 219 to line L-2.

switch 269 is depressed sufllciently to hold the normally open contacts thereof closed. The

spindle rotation push button switches 266, 261

base of the machine far enough to close the normally open contacts thereof. The closing of these contacts establishes a circuit from the line L-I through spindle and feed motor jog push button switch 258, wire 384, and operating solenoid 385 of relay 386 to L2. The energizaticn of the operating solenoid 3850f relay 386 closes the normally open contacts 388, 389 and 3l8 thereof, the former of which closes a circuit from the line Ll through jog push button switch 258, wire 384, contacts 388, wire 284, operating solenoid 285 of themotor control panel 288, wire Energization of the operating solenoid 285 of motor control panel 288 operates the main contacts 286, 281 and 288 thereof to connect the motor 23 to the line to rotate the spindle forward. The closing of contacts 389 and 3I8 of relay 386 establishes circuits hereinafter more specifically referred to, which among other things, causes the feed and rapid traverse motor 2| to rotate.

The motor 23 is so constructed and wired that when the rotation thereof is stopped by depressing either of the push button switches 266 or 261,

288. When either of the push button switches 266 or 261 is depressed with the motor rotating in the reverse direction, the operating solenoid 388 is deenergized and the motor disconnected from the line. Deenergization of the operating solenoid 388 allows the contacts 3I6 to close, establishing a circuit from the wire 213 through the contacts 3 of switch 3l2, wire I, contacts 316, wire 284, operating solenoid 285, etc., of motor control panel 288 toline L2 so long as the motor 23 continues to rotate in a reverse direction; ,Energization-of the operating solenoid 285 of the motor control panel 288 closes the main contacts 286, 281 and 288, which tend to rotate 5 the motor in the opposite direction. When the motor 23 is stopped by depressing either of the push button switches 258, 269 or 268, irrespective of the direction of rotation, the motor coasts or, in other words, the plugging is not effected until the push button is released, since these switches are in series with both sets of contacts of the switch 312.

The spindle feed directional and the spindle rapid traverse controls are so designed that when 25 the directional switch 262 is turned to the left switch 262 is turned to the right, that is, to a position to close the contacts M8, the spindle feed is to the right, likewise, regardless of the direction of rotation of the spindle [9. This is accomplished through the medium of the contacts 295,

296, 291 and 298 of the relay 292, the former two the motor is instantaneouslybrought to rest by being momentarily connected to the line in such a manner that it tends to rotate in the opposite direction. This is referred to as "plugging and is accomplished in the present instance by a switch 3I2, comprising two sets of contacts 3l3 and 3M adapted to be selectively closed while the rotor of the motor is rotating depending upon the direction of rotation. In the present instance when the motor is rotating the spindle l9 forward, the contacts 3I3 are closed, whereas when the motor is rotating in reverse, the contacts 3i4 are closed. The contacts 3I3 of the switch 3I2 are in series circuit with a normally closed set of contacts 3l5 adapted to be opened upon energi'zation of the operating solenoid 285 of the motor control panel 288. When the rotation of the motor 23 is stopped by depressing either of the push button switches 266 or 261, with the motor .rotating in the forward direction, the operating solenoid 285 is deenergized and the motor disconnected from the line. Deenergization of the operating solenoid 285 allows the contacts 3l5 to close which completes a circuit from the line L-l through jog push button switch 258, wire 21l, stop all feeds and spindle rotation push button switch 268, wire 212, jog push but ton switch 269, wire 213, contacts 313 of switch 312, wire 3, contacts 315, wire 299, operating solenoid 388 of motor control panel 288, etc., to line 1-2 so long as the motor 23 continues to rotate in a forwarddirection. Energization of the operating solenoid 388 of the motor panel 288closes the main contacts 38l, 382 and 383 which tend to rotate the motor in the opposite direction.

The contacts 3 of switch 3! are in series circuit with a normally closed set of contacts 3l6 adapted to be opened upon energization of the operating solenoid 388 of the motor control panel of which contacts are normally open, while the latter two are normally closed. The operating solenoid 29l of the relay 292, as previously explained, is energized when the spindle is rotating 40 in reverse and when energized causes a transposition of the control wires to relays 3l9 and 328, which in turn control the energization of the clutch operating solenoids I92 and I93, respectively. The spindle rapid traverse push button switches 264 and 265 always rapid traverse the spindle in the same direction regardless of the position of the directional switch 262, or the direction of rotation of the spindle l9. This is accomplished by a transposition of the control wires by the relays 3l9 and 328 to the operating solenoids 321' and 322 of the motor control panel 323 for the spindle rapid traverse motor 24. However, the switch 262 must be in one or the other of its two on positions before the rapid traverse push button switch 264 or 265 are operative.

With the forego ng in mind, the spindle 19 may be fed towards the left, or in a forward direction, by first turning the feed directional selecting switch- 262 to its left-hand on" position, and subsequently depressing the spindle feed push button 263. Turning the directional selecting switch to the left, closes the contacts 3 thereof, and upon depressing the spindle feed push button switch 263 a circuit is established from the line L-l, through jog push button switch 258, wire 21l, stop all feeds push button switch 26!, wire 324, normally closed contacts 325 of relay 326, wire 321, normally closed contacts 328 of relay 329, wire 338, normally closed contacts 33l of relay 48l wire 333, contacts of spindle start push button 263, wire 334, operating solenoid 335 of relay 336, wire 331, adjustable dial limit switch 284,'wire 338, and limit switch 339 on the spindle head to L-2. At the same time a circuit is completed from wire 334 through the operating solehold 340 of relay 34!, wire 342, adjustable dial limit switch 205 on the spindle-head, wire 344,

and limit switch 223 to L2, which circuit is connected in parallel with the circuit through the operating solenoid 335 of relay 336 and the limit switches 204 and 339. Simultaneously, a third circuit is completed from the wire 334 through transformer 345 to the line L2. The secondary of the transformer 345 is connected by the wires 346 and 341 to the indicating light located in the spindle'feed start push button switch 263. While the spindle I9 is being fed the light is energized regardless of the direction of feed.

Energization of the operating solenoids 335 and 346 of the relays 336 and 34!, respectively, closes the normally open contacts 349 of relay 336 and the normally open contacts 350 of relay 34! in series circuit with the contacts 3!! and 3I8, re-

- spectively, of the directional selecting switch 262.

The closing of the normally open contacts 350 has no eifect n the circuit, since these contacts are in series with contacts 3I8 of the directional selecting switch 262 which are now open.

The closing of the normally open contacts 349 of the relay 336 establishes a circuit from the wire 334 through contacts 3", wire 35!, contacts 349, wire 352, contacts 298. of relay 292, wire 353, and operating solenoid 354 of relay 320 to L2. Energization of the operating solenoid 354 of relay 326 closes the normally open contacts 355, 356, 351 and 358 and opens the normally closed contacts 359 thereof.

The closing of contacts 351 of relay 320 completes a circuit from the wire 353, through the contacts 351, wire 360, solenoid I93, wire 36!, and normally closed solenoid overload contacts 362 to L2. Energization of the solenoid I93 shifts the movable clutch element I89 to the right, as viewed in Fig. 7, that is, in a direction to feed the spindle to the left when the spindle is rotating in the forward direction. The closing of the normally open contacts358 of relay 320 establishes a holding circuit for the relays 336 and 34! from the wire 333, through the contacts 358, wire 334, operating solenoids 335 and 340 of relays 336 and 34!, respectively, and the limit switches 204, 339 and 205, 223, respectively. The holding circuit just referred to continues the feed after the spindle feed push button switch 263 is released. The spindle continues to feed forward until the holding circuit for relay 336 is broken either by the opening of one of the limit switches 204 or 339, by the directional selecting switch 262 being returned to its off position, or by the jog push button switch 258 or the stop all feeds push button switch 26! being depressed. When the holding circuit for the relay 336 is broken, the operating circuit for the solenoid I93 is in turn broken and the movable clutch element I89 allowed to return to its neutral position under the action of the spring !9!.

Assuming that the spindle is rotating in the forward direction and that the feed direction selecting switch 262 is in its left-hand on" position with the contacts 3" thereof closed, when the spindle feed start push button switch 263 is depressed, the spindle will feed towards the left, even though the direction of rotation of the spindle is reversed. This is accomplished by the relay 292, the operating solenoid 29! of which is energized while the spindle is rotating in the reverse direction, as previously explained.

Energization of the operating coil 29! of relay 292 opens the normally closed contacts 29'! and 299 and closes the normally open contacts 296 and 296 thereof, connecting the wire 352 to wire 363 instead of to wire 353, as in the case when the spindle is rotating forwardly. When the spindle feed start push button switch 263 is depressed this establishes a circuit in addition to the circuits established through the relays 336 and 34!, from the wire 334 through contacts 3" of direction selecting switch 262, wire 35!,

contacts 348 of relay 336, wire 352, contacts 296 of relay 292, wire 363, and operating solenoid 364 of relay 3I9 to line L2. Energization of the operating solenoid 364-of relay 3I9 opens the normally closed contact 365 and closes the normally open contacts 366, 361, 368 and 369 thereof. The closing of contacts 368 of relay 3!. establishes a circuit from the wire 363, through contacts 368, wire 310, solenoid I92, and wire 36!, contacts 362 of solenoid overload relay 348 to L2, energizing the solenoid I92 shifting the movable clutch element I89 towards the left, as viewed in Fig. 7, thus operatively connecting the gear I85 with the shaft I82. This would ordinarily rotate the lead screw I12 in the reverse direction, but since the direction of rotation of the spindle I9 has been reversed, the feed is in or to the left. The closing of contacts 369 establishes a holding circuit for relay 336 from wire 333 through contacts 369 to wire 334, thus maintaining relay 336 energized and also maintaining the solenoid I92 and the indicating transformer 345 energized. The spindle continues to feed towards the left as long as it is rotated until the holding circuit just mentioned is broken by either depressing the stop all feeds push button switch 26! or the jog push button switch 258 on the base of the machine, by returning the direction selecting switch 262 to ofi" position, or by the opening of either of the limit switches 264 or 40 339. When the holding circuit for the relay 336 is broken, the operating circuit for the relay 3I9 and thesolenoid I92 is in turn broken and the movable clutch element !89 allowed to return to its neutral position under the action of the spring I90.

Assuming now that it is desired to feed the spindle in the reverse direction or towards the right, the spindle feed selecting switch 262 is turned to its right on position closing the contacts 3I8 thereof. The spindle feed start push button switch 263 when depressed, establishes a circuit from the wire 333 of spindle start push button 263, wire 334,-operating solenoid 335 of relay 336, wire 331, limit switch 204, wire 336, and limit switch 339 to L2. At the same time a circuit is completed through the operating solenoid 340 of relay 34!, wire 342 and limit switch 205, wire 344 and limit switch 223 to L2. Simultaneously, a third circuit is completed from the wire 334, through the transformer 345 to the line L2.

As previously explained, energization of the operating solenoids 335 and 340 of the relays 336 and 34!, respectively, closes the normally open contacts 349 of relay 336 and the normally open contacts 350 of relay 34! in series circuit with the contacts 3!! and 3I8, respectively, of the direction selecting switch 262. The closing of the normally open contacts 350 establishes a circuit from the wire 334 through contacts 3I8, wire 31!, contacts 350, wire 312, normally closed contacts 291 of relay 292, wire 363, and operating solenoid 364 of relay 3I9 to L2. Energization of the operating solenoid 364 of relay 3! 9 closes the 7 normally open contacts 366, 361, 368 and 369 and 

